1. Field of the Invention
The present invention relates to an apparatus and method for performing ink-jet application accurately in application of a liquid material on a smooth member by an ink jet technique in such a manner that data obtained by an image-capturing unit are subjected to image processing to calculate a current position of a groove to be subjected to application and calculate a displacement quantity from a reference position for a next application time to correct the position of an application head and move the application head to the corrected position.
2. Description of the Background Art
The ink jet technique is a technique for discharging a small amount of liquid drops accurately from an ink-jet head using air bubbles or piezoelectric elements. An apparatus for applying a liquid material on a target member by the accurate discharge of liquid drops is an ink-jet application apparatus. The ink-jet application apparatus has recently attracted attention as an apparatus capable of achieving high-definition application. The applicability of the ink-jet application apparatus not only to printing on paper but also to all industrial fields has been explored, so that the ink-jet application apparatus has been already put into practical use.
There has been heretofore proposed a technique in which pattern application is performed on a substrate to eliminate the influence due to a difference in injection state between heads and a positional displacement of the application dots is measured by a camera to calculate the quantity of movement and move the head in XYθ directions to thereby perform correction so that the head approaches a target position. In this manner, the technique can reduce position variation in accordance with each application dot so that a uniform, even and high-quality panel can be produced (e.g. see JP-A-2009-95690).
Factors for determining accuracy of application position in ink-jet application are roughly classified into two factors. The first factor is position variation in accordance with each application dot based on a direction of injection of liquid drops from nozzle holes of an ink-jet application head. The second factor is the degree of coincidence of the nozzle holes of the ink-jet application head with the position of application on a target to be subjected to application.
The technique described in JP-A-2009-95690 can give solution for the first factor but cannot give sufficient solution for the second factor in accordance with the kind of the member to be subjected to application.
In the following description, the member to be subjected to application is a flexible laminated film with long groove-like patterns (hereinafter referred to as scribes) formed in a surface of the film. Although such scribes are formed by laser beams or the like, irradiation position error of laser beams occurs because the film is made of a flexible material.
There may be also conceivable a method in which alignment marks provided at regular intervals are image-captured by a camera to be recognized after the member to be subjected to application is positioned to an application place, so that the positioning state of the member to be subjected to application is measured. However, because the film is heated/cooled in a process before the application process, expansion/contraction arises in the laminated film to cause a positional displacement of the alignment marks. There arises a problem that the position of the nozzle holes of the ink-jet application head is displaced from the position where application should be performed.